Fuel cell vehicle

ABSTRACT

A fuel cell vehicle provided with an exhaust duct structure is capable of reliably diluting hydrogen flowing into an exhaust duct. The fuel cell vehicle includes a vehicle body, an air-cooled fuel cell mounted in the vehicle body to generate power by allowing hydrogen gas and oxygen in air to react with each other, an exhaust duct through which exhaust air of the fuel cell is guided to a rear end of the vehicle body and is discharged outside the fuel cell vehicle, and a fan guiding air into the exhaust duct to dilute hydrogen in the exhaust duct.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of Japanese PatentApplication No. 2015-210392, filed on Oct. 27, 2015, the entire contentsof which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a fuel cell vehicle.

Description of the Related Art

There is known a fuel cell vehicle that travels by being driven by anelectric motor powered by a fuel cell. Conventional fuel cell vehicleseach have an exhaust duct structure including an exhaust duct connectedto a rear side of a fan box provided with a fan for guiding air to afuel cell. The exhaust duct is divided into a first exhaust duct throughwhich air having cooled the fuel cell is guided, and a second exhaustduct avoiding a vehicle body frame and connected to a rear side of thefirst exhaust duct, the second exhaust duct discharging the air from thefirst exhaust duct from a rear end of a vehicle body therethrough.

The exhaust duct is used not only to discharge humid exhaust air emittedfrom the fuel cell during power generation, but also to dilute anddischarge hydrogen discharged from an anode of the fuel cell at regularintervals to the outside of the fuel cell vehicle to maintain steadypower generation of the fuel cell.

SUMMARY OF THE INVENTION

Unfortunately, an exhaust duct structure of a conventional fuel cellvehicle causes difficulty in allowing a cross-sectional shape of theexhaust duct to be identical throughout overall length of the exhaustduct as a matter of convenience of a shape of the vehicle body and ashape of the vehicle body frame.

The exhaust duct whose cross-sectional shape varies in a flowingdirection as described above may cause a flow of hydrogen to partiallystagnate to result in insufficient dilution of the hydrogen.

To solve the problems described above, it is an object of the presentinvention to provide a fuel cell vehicle provided with an exhaust ductstructure capable of reliably diluting hydrogen, which is surplushydrogen contained in exhaust air of a fuel cell, flowing into theexhaust duct.

To achieve the above object, an aspect of the present invention providesa fuel cell vehicle including a vehicle body, an air-cooled fuel cellmounted in the vehicle body to generate power by allowing hydrogen gasand oxygen in air to react with each other, an exhaust duct throughwhich exhaust air of the fuel cell is guided to a rear end of thevehicle body and is discharged outside the fuel cell vehicle, and a fanguiding air into the exhaust duct to dilute hydrogen in the exhaustduct.

In preferred embodiments of the above aspect, the following modes may beprovided.

It may be desired that the fan is provided in a lower portion of theexhaust duct, and is arranged to blow rearward of the vehicle body.

It may be further desired that a dilution accelerating wall providedinside the exhaust duct and facing the fan to disperse a flow generatedby the fan into the exhaust duct for acceleration of dilution ofhydrogen.

It may be desired that the fuel cell includes a surplus hydrogen exhaustpipe discharging unreacted surplus hydrogen. The exhaust duct includes asurplus hydrogen guide passage through which the surplus hydrogen isguided from the surplus hydrogen exhaust pipe into the exhaust duct, thesurplus hydrogen being guided to above the fan and on an upstream sideof a flow of exhaust air in the exhaust duct.

It may be desired that the fan is disposed in a central portion of theexhaust duct in a width direction of the vehicle body. The surplushydrogen guide passage includes a tunnel cover covering a plurality ofsurplus hydrogen guide holes penetrating a wall of the exhaust duct tocommunicate with the surplus hydrogen exhaust pipe, the tunnel covercollecting the surplus hydrogen guided into the exhaust duct through thesurplus hydrogen guide holes to collect the surplus hydrogen to acentral portion of the exhaust duct in a width direction of the vehiclebody, the tunnel cover including a plurality of exhaust holes.

This fuel cell vehicle provided with an exhaust duct structure iscapable of reliably diluting hydrogen flowing into an exhaust duct.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left side view of a fuel cell vehicle according to anembodiment of the present invention;

FIG. 2 is a left side view of the fuel cell vehicle according to theembodiment of the present invention, with its exteriors being detached;

FIG. 3 is a perspective view of the fuel cell vehicle according to theembodiment of the present invention, with its exteriors being detached;

FIG. 4 is a longitudinal sectional view of an exhaust duct structure ofthe fuel cell vehicle according to the embodiment of the presentinvention;

FIG. 5 is a front view of the exhaust duct of the fuel cell vehicleaccording to the embodiment of the present invention;

FIG. 6 is a left side view of the exhaust duct of the fuel cell vehicleaccording to the embodiment of the present invention;

FIG. 7 is a rear view of the exhaust duct of the fuel cell vehicleaccording to the embodiment of the present invention;

FIG. 8 is a perspective view of the exhaust duct of the fuel cellvehicle according to the embodiment of the present invention viewed froman obliquely left forward and upward direction;

FIG. 9 is a perspective view of the exhaust duct of the fuel cellvehicle according to the embodiment of the present invention viewed froman obliquely left forward and downward direction; and

FIG. 10 is a perspective view of the exhaust duct of the fuel cellvehicle according to the embodiment of the present invention viewed froman obliquely left backward direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, an embodiment of a fuel cell vehicle according to thepresent invention will be described with reference to FIGS. 1 to 10.

FIG. 1 is a left side view of the fuel cell vehicle according to theembodiment of the present invention.

FIG. 2 is a left side view of the fuel cell vehicle according to theembodiment of the present invention, with its exteriors, for example,covers and a seat being detached.

FIG. 3 is a perspective view of the fuel cell vehicle according to theembodiment of the present invention, with its exteriors, for example,covers and a seat being detached.

Note that expressions of front-and-rear, up-and-down, and left-and-rightin the present embodiment are based on reference to a rider onboard afuel cell vehicle 1. In FIGS. 1 to 3, a solid line arrow F representsforward of the fuel cell vehicle 1, and a solid line arrow R representsreward of the fuel cell vehicle 1.

As shown in FIGS. 1 to 3, the fuel cell vehicle 1 according to thepresent embodiment travels by being driven by an electric motor 3powered by a fuel cell 2. The fuel cell vehicle 1 is a motorcycle ofscooter type, and also a fuel cell powered bicycle traveling by thepower of the fuel cell 2. The fuel cell vehicle 1 may be a tricycle.

The fuel cell vehicle 1 includes a vehicle body 5 extending forward andrearward, a front wheel 6 as a steered wheel, a steering mechanism 7supporting the front wheel 6 in a steerable manner, a rear wheel 8 as adriving wheel, a swing arm 9 supporting the rear wheel 8 so as to beswingable in the up and down direction, and the electric motor 3 whichgenerates driving power of the rear wheel 8.

The vehicle body 5 includes a frame 11 extending forward and rearward ofthe vehicle, an exterior 12 covering the frame 11, and a seat 13disposed above a rear half part of the frame 11.

Further, the vehicle body 5 includes a fuel cell 2, a fuel tank 15configured to store high pressure gas of hydrogen as a fuel to be usedfor power generation in the fuel cell 2, a rechargeable battery 16configured to supplement power of the fuel cell 2, a power managementapparatus 17 configured to adjust output voltage of the fuel cell 2 andcontrol power distribution between the fuel cell 2 and the rechargeablebattery 16, an inverter 18 configured to convert DC power outputted bythe power management apparatus 17 into three-phase AC power and outputsit to the electric motor 3 to operate the electric motor 3, and avehicle controller 19 configured to comprehensively control thosementioned before.

A power train of the fuel cell vehicle 1 includes the fuel cell 2 andthe rechargeable battery 16, is a system which appropriately utilizespower of each power supply depending on travelling conditions of thevehicle, power generation conditions of the fuel cell 2, and powerstorage conditions of the rechargeable battery 16. The fuel cell vehicle1 generates regenerative power at the electric motor 3 duringdeceleration. The rechargeable battery 16 and the fuel cell 2, which arepower sources of the vehicle, are connected in parallel to the inverter18 and supply power to the electric motor 3. The rechargeable battery 16stores regenerative power generated at the electric motor 3 when thefuel cell vehicle 1 decelerates, and power generated by the fuel cell 2.

The frame 11 is made up of a plurality of steel hollow pipes combinedinto a single body. The frame 11 includes a head pipe 21 disposed abovethe front end of the frame 11, an upper down-frame 22 extending from acentral part of the head pipe 21 in a rearwardly and downwardly inclinedmanner, a lower down-frame 23 disposed below the head pipe 21 andextending in a rearwardly and downwardly inclined manner, a pair of leftand right lower frames 24, a pair of left and right upper frames 25, apivot shaft 26, an upper bridge frame 27, a lower bridge frame 28, aguard frame 29, and a mounted-instrument protection frame 30.

The head pipe 21 supports the steering mechanism 7 so as to besteerable, that is, to be swingable in the left and right direction ofthe fuel cell vehicle 1.

The pair of left and right lower frames 24 are disposed in the left andthe right of the lower down-frame 23 and connected to a lower part ofthe head pipe 21. The pair of left and right lower frames 24 eachinclude a front-side inclined portion extending from a connected portionwith the head pipe 21 substantially in parallel along the lowerdown-frame 23 and in a rearwardly and downwardly inclined manner, afront-side curved portion curved rearwardly at a lower end of thefront-side inclined portion, and a straight portion extendingsubstantially horizontally from a rear end of the front-side curvedportion toward rearward of the vehicle body 5 in a linear manner untilreaching a central portion of the vehicle body 5, that is, a centralportion in the front and rear direction of the fuel cell vehicle 1. Thepair of left and right lower frames 24 each include a rear-side curvedportion curved toward rearward and upward from a rear end part of thestraight portion, a rear-side inclined portion extending from an upperend part of the rear-side curved portion in a rearwardly and upwardlyinclined manner, and an upper and lower frame joining part connectingthe rear-side inclined portion to the upper frame 25. Spacing betweenthe left and right lower frames 24 is wider than that between the leftand right upper frames 25.

A near-head-pipe bridge frame 34 is constructed between upper parts ofthe left and right lower frames 24. The near-head-pipe bridge frame 34extends in a linear manner substantially in the left and right directionof the fuel cell vehicle 1. Each of the left and right lower frames 24includes a foot rest bracket 31 a. The foot rest bracket 31 a supports afoot board 31, which is disposed on the outer side of the front-sidecurved portion, from below. A rider can lay its foot on the foot board31.

The lower frame 24 being disposed on the left side of the vehicle body 5includes a side stand bracket (not shown). The side stand bracket (notshown) is provided with a side stand (not shown) configured to make thefuel cell vehicle 1 stand by itself in a leftwardly inclined manner. Theside stand swings between an erected position for making the fuel cellvehicle 1 stand by itself, and a retracted position for making it stayalong the vehicle body 5 so as not to impede travelling.

The pair of left and right upper frames 25 are connected to a centralpart in the up-and-down direction of the front-side inclined portion ofthe lower frame 24 in a front half part of the vehicle body 5. The pairof left and right upper frames 25 each include, horizontal portionsextending from a connected portion with the front-side inclined portionof the lower frame 24 toward rearward of the vehicle body 5 in asubstantially horizontal manner, and rear end parts being rear ends ofthe horizontal portions of the pair of left and right upper frames 25,the rear end parts being significantly inclined rearwardly and upwardlyin the rear half part of the vehicle body 5 and above the rear wheel 8,the rear end parts curved inwardly in the left and right direction ofthe vehicle body 5 to come close to each other to an extent of aboutthickness (width size) of the rear wheel 8.

The pivot shaft 26 is constructed between the left and right upperframes 25 in the rear half part of the vehicle body 5. The pivot shaft26 is constructed between a pair of left and right brackets 26 a. Eachof the brackets 26 a is located below the upper frame 25 and in the rearof a merging portion (upper and down frame joining part) between theupper frame 25 and the lower frame 24. Each of the brackets 26 a isconnected to the horizontal portion of the upper frame 25, and to therear-side inclined portion of the lower frame 24.

The upper bridge frame 27 is constructed between the front end parts ofthe left and right upper frames 25. The upper bridge frame 27 extendssubstantially linearly in the left and right direction of the vehiclebetween the left and right upper frames 25 to interconnect the left andright upper frames 25.

The lower bridge frame 28 is constructed between the front-side curvedportions of the left and right lower frames 24. The lower bridge frame28 extends substantially linearly in the left and right direction of thevehicle between the left and right lower frames 24 to interconnect theleft and right lower frames 24.

The guard frame 29 is constructed between the rear-side curved portionsof the left and right lower frames 24. The guard frame 29 extendsrearwardly and downwardly from a connected portion with the left andright lower frames 24, and extends into a rearwardly declined U-shape soas to enlarge the internal space of the frame 11. The guard frame 29 isprovided with a center stand 33 configured to make the fuel cell vehicle1 stand by itself in an upright state. The center stand 33 swingsbetween an erected position for making the fuel cell vehicle 1 stand byitself, and a retracted position for making it stay along the vehiclebody 5 so as not to impede travelling.

The upper down-frame 22 is constructed between the head pipe 21 and theupper bridge frame 27.

The lower down-frame 23 includes an upper end part connected to acentral part in the left and right direction of the fuel cell vehicle 1of a near-head-pipe bridge frame 34 constructed between the left andright lower frames 24, and a lower end part connected to a central partin the left and right direction of the fuel cell vehicle 1 of the lowerbridge frame 28.

The mounted-instrument protection frame 30 is provided above the rearhalf part of the upper frame 25. The mounted-instrument protection frame30 supports and secures the fuel cell 2 to the fuel cell vehicle 1. Apart of the mounted-instrument protection frame 30 can be attached anddetached to and from the upper frame 25.

The seat 13 extends forward and rearward covering an upper section ofthe rear half part of the frame 11. The seat 13 is of a tandem type andincludes a front half part 13 a on which the rider is to be seated, arear half part 13 b on which a passenger is to be seated, and aninclined part 13 c between the front half part 13 a and the rear halfpart 13 b.

Here, a space surrounded by the left and right upper frames 25 and theleft and right lower frames 24 is referred to as a center tunnel region35. A space surrounded by the rear half part of the upper frame 25,exterior 12, and the seat 13 as an instrument mounting region 36. Aspace in the rear of the center tunnel region 35 and below theinstrument mounting region 36 as a tire house region 37.

The center tunnel region 35 accommodates the fuel tank 15. In the fuelcell vehicle 1 of a motor-scooter type according to the presentembodiment, the center tunnel region 35 is disposed along the front andrear direction of the fuel cell vehicle 1 and between left and rightfoot boards 31 on which the rider places its foot, and rises higher thanthe foot board 31 such that the foot resting region of the foot board 31is divided into left and right sections. In other words, the foot board31, which serves as the foot resting region, is disposed in the left andright of the center tunnel region 35, and the fuel tank 15 is disposedbetween the left and right foot boards 31.

The instrument mounting region 36 accommodates the rechargeable battery16, the power management apparatus 17, and the fuel cell 2 in this orderfrom the front side of the vehicle body 5. The mounted-instrumentprotection frame 30 protects the front end part, the central part, therear end part, and a side part ranging from the central part to the rearend part of the instrument mounting region 36.

The mounted-instrument protection frame 30 surrounds the instrumentmounting region 36 and protects instruments to be mounted in theinstrument mounting region 36. The mounted-instrument protection frame30 includes a front protection frame 30 a disposed in the front end partof the instrument mounting region 36, the front protection frame 30 abeing constructed between the left and right upper frames 25 in anupwardly convex arch shape, a center protection frame 30 b disposed in acentral part of the instrument mounting region 36 and in the rear of amerging spot between the upper frame 25 and the lower frame 24, thecenter protection frame 30 b being constructed between the left andright upper frames 25 in an upwardly convex arch shape, a pair of leftand right rear protection frames 30 c disposed at a rear end part of theinstrument mounting region 36, the pair of left and right rearprotection frames 30 c being connected to a portion where each of theleft and right upper frames 25 is curved inwardly, the pair of left andright rear protection frames 30 c extending rearward and obliquelyupward from the curved portion, a pair of left and right side protectionframes 30 d extending rearward from each of the left and right of thecenter protection frame 30 b to be connected to the upper end parts ofthe rear protection frames 30 c, the pair of left and right sideprotection frames 30 d reaching the rear end part of the vehicle body 5,a bracket 30 e constructed between rear end parts of the left and rightside protection frames 30 d.

The left and right upper frames 25 are bent at a spot where the lowerends of the front protection frame 30 a are joined thereto, increase thespacing therebetween toward the rear of the fuel cell vehicle 1. Theleft and right upper frames 25 are bent at a spot where the lower endsof the center protection frame 30 b are joined thereto, and extend tothe rear of the fuel cell vehicle 1. Thus, the center protection frame30 b has a larger width and a larger height than those of the frontprotection frame 30 a. The rear protection frame 30 c and the pair ofthe left and right side protection frames 30 d are integrated.

The rear protection frame 30 c and the pair of left and right sideprotection frames 30 d are detachably interconnected to the centerprotection frame 30 b and the upper frames 25, thereby supporting thefuel cell 2.

A rear wheel 8 is disposed in the tire house region 37.

Between the instrument mounting region 36 and the tire house region 37,a rear fender 38 as a partition member for dividing respective regionsis provided.

The exterior 12 includes, a front leg-shield cover 41 covering a fronthalf part of the vehicle body 5, a front frame cover 42 disposed abovethe center of the vehicle body 5 and covering an upper section of theupper frame 25 such as the center tunnel region 35, and a frame cover 43disposed in a rear half part of the vehicle body 5 and covering a lowerportion of the seat 13.

The frame cover 43 along with the seat 13 surrounds the instrumentmounting region 36. The instrument mounting region 36 is a closed spacesurrounded by the seat 13, the frame cover 43, and the rear fender 38.The instrument mounting region 36 easily and securely controls flow ofair to the fuel cell 2 by means of a vent hole (not shown) provided inan appropriate area of the frame cover 43 or the rear fender 38, andalso easily and securely controls flow of air as a cooling wind to anapparatus, which needs to be cooled. The instrument mounting region 36allows air to enter from, for example, a joint of each cover (such asthe front frame cover 42, and a frame cover 43).

The steering mechanism 7 is disposed in a front section of the vehiclebody 5 and swings in the left and right direction centering on the headpipe 21 of the frame 11, thereby enabling steering of the front wheel 6.The steering mechanism 7 includes a handle 45 provided in a top part,and a pair of left and right front forks 46 interconnecting the handle45 and the front wheel 6, and the pair of left and right front forks 46extending in the up and down direction slightly inclined rearwardly. Theleft and right front forks 46 have a telescopic structure that can beelastically expanded and contracted. An axle (not shown) for rotatablysupporting the front wheel 6 is constructed between lower end parts ofthe left and right front forks 46. The front fender 47 is disposed abovethe front wheel 6. The front fender 47 is located between the left andright front forks 46, and secured to the front fork 46.

The front wheel 6 is a driven wheel that is rotatable about the axleconstructed between the lower end parts of the left and right frontforks 46.

The swing arm 9 swings in the up and down direction about the pivotshaft 26 as a rotational center extending in the left and rightdirection of the vehicle body 5. The swing arm 9 rotatably supports therear wheel 8 between a pair of arms extending in the front and reardirection on left and right sides of the vehicle body 5, respectively. Arear suspension 48 is constructed between the frame 11 and the swing arm9. The upper end part of the rear suspension 48 is swingably supportedat the rear end part of the upper frame 25. The lower end part of therear suspension 48 is swingably attached to the rear end part of theswing arm 9. The rear suspension 48 buffers the swinging of the swingarm 9.

The swing arm 9 accommodates the electric motor 3 rotationally drivingthe rear wheel 8, and an inverter 18 converting DC power supplied fromthe fuel cell 2 into AC power to supply it to the electric motor 3.

The electric motor 3 rotationally drives the rear wheel 8 with powersupplied from the fuel cell 2 or the rechargeable battery 16, therebycausing the fuel cell vehicle 1 to travel. The electric motor 3 isaccommodated in a rear part of the swing arm 9 and coaxially disposedwith the axle of the rear wheel 8. The electric motor 3 is integrallyassembled to the swing arm 9 to constitute a unit-swing-type swing arm.

The inverter 18 is accommodated in a front part of the swing arm 9, anddisposed between the pivot shaft 26 and the electric motor 3. Theinverter converts DC power outputted by the power management apparatus17 into three-phase AC power, and adjusts the rotational speed of theelectric motor 3 by altering the frequency of the AC power.

The rear wheel 8 is the driving wheel being supported by the axle (notshown) to which driving force is transferred from the electric motor 3.

The fuel cell 2 generates power by causing reaction between a fuel andan oxidizing agent. The fuel cell 2 is an air-cooled fuel cell systemgenerating power by using a high pressure gas, for example, hydrogen gasas the fuel, and oxygen in the air as the oxidizing agent, and is cooledby using air.

The fuel cell 2 is disposed on the rear half side of the instrumentmounting region 36. The fuel cell 2 is disposed below the seat 13 over arange from an inclined part between the front half part 13 a and rearhalf part 13 b to the rear half part 13 b. That is, in the side view ofthe vehicle, the fuel cell 2 is disposed between the rear half part 13 bof the seat 13, on which the passenger is to be seated, and the rearwheel 8 and the swing arm 9.

The fuel cell 2 has a cuboidal shape having a long side extending in thefront and rear direction of the vehicle body 5, and is disposed in theinstrument mounting region 36 in a posture in which its front face, inwhich the intake port 2 a is disposed, faces forward and obliquelydownward, and its back face, in which the exhaust port 2 b is disposed,faces rearward and obliquely upward. That is, the fuel cell 2 is securedto the frame 11 in a forward leaning posture in which its front side islocated lower than its rear side. The upper part of the fuel cell 2 issecured to a mounted instrument protection frame 30 and the lower partof the fuel cell 2 is secured to the upper frame 25.

The fuel cell 2 includes a plurality of flat modules interconnected fromthe front side toward the rear side. The fuel cell 2 includes a filter(not shown), an intake shutter (not shown), a fuel cell stack (notshown), a fan (not shown), and an exhaust shutter (not shown), which areinterconnected by being superposed on each other in a laminated state inorder from the front side. A fuel cell control unit (not shown) isprovided on the top face of the fuel cell 2.

The intake shutter includes an openable/closable intake port 2 a of air,and configured to control the amount of air introduced to the fuel cellstack by opening/closing the intake port 2 a. The intake shutterconfigured to constitute a circulation path for circulating air in thefuel cell 2 by closing the intake port 2 a. The exhaust shutter includesan openable/closable exhaust port 2 b of air and configured toconstitute the circulation path for circulating air in the fuel cell 2by closing the exhaust port 2 b. In other words, the fuel cell 2includes the openable/closable intake port 2 a in the front face, andthe openable/closable exhaust port 2 b in the back face, and configuredto cause air to be circulated in the fuel cell 2 by closing the intakeport 2 a and the exhaust port 2 b.

The fuel cell stack causes electrochemical reaction between oxygencontained in the air drawn through the intake port and hydrogen suppliedfrom the fuel tank 15 to generate power, and produces a wet excess gasafter generation.

The fan generates intake negative pressure for drawing air in theinstrument mounting region 36 from the intake port into the fuel cell 2,while drawing out the excess gas from the fuel cell stack and dischargesit from the exhaust port. The flow of air being caused by the fan isused for the power generation in the fuel cell stack, as well as for thecooling of the fuel cell 2.

An exhaust duct 52 is provided in the rear of the fuel cell 2. The fanof the fuel cell 2 draws out excess gas from the fuel cell stack anddischarges it to the exhaust duct 52. The front end part of the exhaustduct 52 is airtightly connected to a box, which is a frame body of theexhaust shutter, of the fuel cell 2. The exhaust duct 52 includes anexhaust port 52 a opened toward rearwardly downward, and rearwardlyupward at the rear end of the vehicle body 5. The exhaust duct 52 guidesexhaust gas (excess gas) ejected from the fan of the fuel cell 2 to theexhaust port 52 a and discharges it to the rear of the vehicle body 5.

The exhaust port 52 a is disposed higher than the exhaust face (backface), and preferably at the upper end part of the rear section of theexhaust duct 52. In other words, the upper edge part of the exhaust port52 a is disposed at a position higher than the exhaust port of the fuelcell 2. As a result of having the exhaust port 52 a disposed to behigher than the exhaust face (back face) of the fuel cell 2, the exhaustduct 52 guides a wet excess gas containing unreacted hydrogen gas to theexhaust port 52 a and securely discharge it from the vehicle body 5.

The fuel tank 15 is a high-pressure compressed hydrogen storage system.The fuel tank 15 includes a pressure vessel 55 made of carbon fiberreinforced plastic (CFRP), or being a composite vessel made from analuminum liner, a fuel filling joint 57 having a fuel filling port 56, afuel filling main valve 58, a fuel supply main valve 59 integrallyincluding a shut-off valve (not shown) and a regulator (not shown), anda secondary pressure reducing valve (not shown).

The pressure vessel 55 is a composite vessel made from an aluminum linerwhich stores hydrogen gas as fuel of the fuel cell 2. The fuel tank 15stores, for example, hydrogen gas of about 70 megapascal (MPa.) Thepressure vessel 55 includes a cylinder-shaped barrel part, and adome-shaped mirror plate provided on front and rear end faces of thebarrel part. The pressure vessel 55 is disposed in the center tunnelregion 35 with the central axis of the cylindrical barrel being alignedalong the front and rear direction of the vehicle body 5. The pressurevessel 55 is surrounded by a pair of upper frames 25, a pair of lowerframes 24, a lower bridge frame 28, and a guard frame 29, and isrobustly protected against load due to turning over or collision of thefuel cell vehicle 1.

The pressure vessel 55 is supported in the center tunnel region 35 by aclamp band 61 constructed between an upper frame 25 disposed at one sideof the vehicle body 5, for example, the upper frame 25 disposed at theright side of the vehicle body 5, and a lower frame 24 disposed atanother side of the vehicle body, for example, the lower frame 24disposed at the left side of the vehicle body 5. The pressure vessel 55is placed on a lower clamp band, for example, a lower half part of theclamp band 61 being constructed between the right side upper frame 25and an left side lower frame 24, and is clamped by the upper clamp band,for example, an upper half part of the clamp band 61 to be sandwiched.Note that the clamp band 61 may be constructed between the upper frame25 disposed at the left side of the vehicle body 5 and the lower frame24 disposed at the right side of the vehicle body 5.

The fuel filling joint 57 is disposed outside of the center tunnelregion 35, more specifically, rearwardly upward of the center tunnelregion 35, and at the front end part of the instrument mounting region36. The fuel filling joint 57 is disposed to be higher than or justabove the rechargeable battery 16. The fuel filling joint 57 is securedto the joint bracket 30 f being constructed between the upper parts ofthe front protection frame 30 a and the center protection frame 30 b ofthe mounted-instrument protection frame 30. The fuel filling joint 57extends toward upward, and slightly leftward of the vehicle body 5 suchthat a facility side joint can be inserted from the upper side and leftside of the vehicle body at the time of fuel filling. The fuel fillingjoint 57 is covered and hidden by the fuel filling port lid 62 beingdisposed at the front end of the seat 13. The fuel filling port lid 62is supported to the seat 13 via a hinge mechanism (not shown), andopens/closes by being swung. The fuel filling joint 57 has a fuelfilling port 56 as an inlet for introducing high pressure gas ofhydrogen as a fuel into the fuel tank 15.

The fuel filling port 56 is disposed at a top part of the fuel fillingjoint 57. The fuel filling port 56 is oriented toward the upper left ofthe vehicle body 5. In filling the fuel tank 15 with fuel, the upward ofthe fuel filling port 56 is opened to the atmosphere in a state in whichthe fuel filling port lid 62 is opened. Thus, in charging high pressuregas, for example, hydrogen gas as fuel, into the fuel tank 15, even ifthe high pressure gas leaks, the leaked fuel diffuses toward the upwardof the fuel cell vehicle 1 without residing therein.

A fuel filling main valve 58 and a fuel supply main valve 59 areintegrated and incorporated in a tank valve 63 provided on the top partof the rear-side mirror plate of the pressure vessel 55. The tank valve63 is disposed in a space surrounded by the guard frame 29. The fuelsupply main valve 59 includes a shut-off valve (not shown) and a primarypressure reducing valve (not shown). The fuel filling main valve 58 andthe shut-off valve of the fuel supply main valve 59 are an on-off valveusing an electromagnetic valve. The primary pressure reducing valve andthe secondary pressure reducing valve of the fuel supply main valve 59successively reduce and thereby adjust the pressure of the high pressurefuel gas from the pressure vessel 55.

The rechargeable battery 16 is a box-shaped lithium ion battery. Therechargeable battery 16 is disposed in the front end part of theinstrument mounting region 36 and between the rear half part of thepressure vessel 55, that is, the rear half part of the cylindricalbarrel and the rear-side mirror plate, and the front half part 13 a ofthe seat 13.

Note that, the fuel cell vehicle 1 includes, besides the rechargeablebattery 16, a second rechargeable battery (not shown) supplying, forexample, 12V-based power as a power supply for meters (not shown) andlights (not shown). The second rechargeable battery is disposed aroundthe head pipe 21, for example, beside the right side of the head pipe21.

In the fuel cell vehicle 1, even if hydrogen gas as fuel leaks from thefuel filling port 56, the hydrogen gas, which is lighter than air, movesup, thus diffusing to the outside of the fuel cell vehicle 1 withoutresiding within the fuel cell vehicle 1. Even if hydrogen gas as fuelleaks from the fuel filling main valve 58 or the fuel supply main valve59, the hydrogen gas moves toward the tire house region 37, thusdiffusing to the outside of the fuel cell vehicle 1 without residingwithin the fuel cell vehicle 1.

The power management apparatus 17 is disposed between the rechargeablebattery 16 and the fuel cell 2 in the instrument mounting region 36, andis secured to the frame 11. Note that the power management apparatus 17may be disposed along with the rechargeable battery 16 in a samewaterproof case.

By disposing the rechargeable battery 16, the power management apparatus17, and the fuel cell 2 in a manner as described above, it becomespossible to dispose apparatuses adjoining to each other in theelectrical connection to be closer to each other as much as possible,thus shortening the wiring length between the apparatuses, and reducingthe weight relating to the wiring.

The vehicle controller 19 is disposed around the head pipe 21 being arelatively high place in the fuel cell vehicle 1, for example, besidethe left side of the head pipe 21 corresponding to the opposite side ofthe second rechargeable battery, which supplies 12V-based power.

Next, an exhaust duct structure of the fuel cell vehicle 1 will bedescribed in detail.

FIG. 4 is a longitudinal sectional view of the exhaust duct structure ofthe fuel cell vehicle according to the embodiment of the presentinvention.

FIG. 5 is a front view of the exhaust duct of the fuel cell vehicleaccording to the embodiment of the present invention.

FIG. 6 is a left side view of the exhaust duct of the fuel cell vehicleaccording to the embodiment of the present invention.

FIG. 7 is a rear view of the exhaust duct of the fuel cell vehicleaccording to the embodiment of the present invention.

FIG. 8 is a perspective view of the exhaust duct of the fuel cellvehicle according to the embodiment of the present invention viewed froman obliquely left forward and upward direction.

FIG. 9 is a perspective view of the exhaust duct of the fuel cellvehicle according to the embodiment of the present invention viewed froman obliquely left forward and downward direction.

FIG. 10 is a perspective view of the exhaust duct of the fuel cellvehicle according to the embodiment of the present invention viewed froman obliquely left backward direction.

As shown in FIGS. 4 to 10, the exhaust duct structure 69 of the fuelcell vehicle 1 according to the present embodiment includes the vehiclebody 5, the air-cooled fuel cell 2 mounted in the vehicle body 5 togenerate power by allowing hydrogen gas and oxygen in air to react witheach other, the exhaust duct 52 through which exhaust air of the fuelcell 2 is guided to a rear end of the vehicle body 5 and is dischargedoutside the fuel cell vehicle, and a dilution fan 71 guiding air intothe exhaust duct 52 to dilute hydrogen in the exhaust duct 52.

The exhaust duct structure 69 includes a dilution accelerating wall 72provided inside the exhaust duct 52 and facing the dilution fan 71 todisperse a flow generated by the dilution fan 71 into the exhaust duct52 for acceleration of dilution of hydrogen.

The exhaust duct structure 69 includes an exterior 12 with which thevehicle body 5 is covered, and the exterior 12 has a first joint portion75 fitted into at least one first exhaust port 73.

The fuel cell 2, for example, is a polymer electrolyte fuel cell (PEFC).The fuel cell 2 has at least one of cell stack including a large numberof unit cells stacked with each other. Each of the unit cells includesan anode to which hydrogen is supplied, a cathode to which oxygen in airis supplied, and a laminate sandwiched between the anode and thecathode, the laminate including a dispersion layer, a catalytic layer, asolid polymer electrolyte film allowing a hydrogen ion to be selectivelypermeated, a catalytic layer, and a dispersion layer. The fuel cell 2 isan electrochemical system generating power using an electrochemicalreaction between hydrogen supplied from the fuel tank 15 and oxygencontained air sucked through the intake port 2 a, as well as water as abyproduct.

Surplus air after reaction with hydrogen and air having cooled cellstacks are discharged through the exhaust port 2 b as exhaust air of thecathode.

Hydrogen is generally supplied to the anode via hydrogen supply piping(not illustrated), including a circulation path, according toconsumption of hydrogen in the fuel cell. However, to prevent or reducereduction in hydrogen concentration, caused by nitrogen that inevitablypermeates the cell stack from an air path side, which is the cathodeside, as a reaction of the fuel cell continues, and thus to preventreduction in reaction efficiency due to the reduction in hydrogenconcentration for steady power generation, and to discharge moistureproduced by the reaction, the fuel cell 2 purges hydrogen gas from theanode into the exhaust duct 52 at regular intervals via a surplushydrogen exhaust pipe 76 and an exhaust valve 77. That is, the fuel cell2 includes the surplus hydrogen exhaust pipe 76 and the exhaust valve 77to discharge unreacted surplus hydrogen into the exhaust duct 52.

The exhaust duct 52 discharges humid exhaust air, which is emitted fromthe fuel cell 2 during power generation, to the outside of the fuel cellvehicle 1, and dilutes and discharges hydrogen, which is emitted byhydrogen gas purge maintaining steady power generation of the fuel cell2 and discharged into the exhaust duct 52, to the outside of the fuelcell vehicle 1. The exhaust duct 52 is a molding made of conductiveresin.

The exhaust duct 52 is coupled to the exhaust port 2 b of the fuel cell2, and is coupled to the exterior 12 at the rear end of the vehicle body5. The exhaust duct 52 includes a first duct member 85, and a secondduct member 87 coupled to the first duct member 85.

The first duct member 85 integrally includes a rectangular cylindricalconnection portion 81, and a first partition wall 83 partitioning a partof an exhaust air path 82. The connection portion 81 is air-tightlyconnected to the fuel cell 2.

The second duct member 87 is coupled to a rear portion of the connectionportion 81 and the first partition wall 83 at a divided face 86 as adivided portion of a pair of sidewalls 85 a and 85 c facing each otheramong sidewalls 85 a, 85 b, and 85 c partitioning the exhaust air path82, thereby partitioning other portions of the exhaust air path 82.

That is, the exhaust duct 52 is vertically divided by the divided face86 formed by the sidewalls 85 a and 85 c.

The exhaust air path 82 includes a first exhaust air path 89 extendingfrom the connection portion 81 between the exhaust duct 52 and the fuelcell 2 to the rear end of the vehicle body 5, and a second exhaust airpath 91 branching from an intermediate portion of the first exhaust airpath 89 to extend downward.

The first exhaust air path 89 is connected to the exhaust port 2 b ofthe fuel cell 2, and linearly extends upward to the rear end of thevehicle body 5. The first exhaust air path 89 has a wedge-shapenarrowing vertically and horizontally from an upstream side connectingto the exhaust port 2 b of the fuel cell 2 toward a downstream side, andhas a substantially rectangular cross section of a flow channel. Thefirst exhaust air path 89 includes a portion from the branching portionof the second exhaust air path 91 to the downstream side, having a lowerreduction rate of a flow channel cross-sectional area than that in aportion from the upstream side to a branching portion of the secondexhaust air path 91.

The first exhaust air path 89 includes at least one first exhaust port73 opening toward the rear of the vehicle body 5. The at least one firstexhaust port 73 has a right and left pair of exhaust ports 73 a and 73b, opening toward the rear of the vehicle body 5. The pair of exhaustports 73 a and 73 b branches in the shape of “V” on a downstream side (arear side of the vehicle) from the branching portion of the firstexhaust air path 89 and the second exhaust air path 91 to allow exhaustair in the exhaust duct 52 to smoothly and separately flow.

The first exhaust port 73 includes an electrically conductive first meshfilter 92. The first mesh filter 92 prevents foreign objects in a sizeof a few millimeters to a centimeter from entering the exhaust duct 52while maintaining a smooth flow of exhaust air in the first exhaust port73.

The second exhaust air path 91 hangs obliquely backward and downwardalong a tangential direction of the rear fender 38. The second exhaustair path 91 has a substantially uniform tube shape from the branchingportion with the first exhaust air path 89 toward its lower end. Thesecond exhaust air path 91 has a flow channel cross section in the shapeof a trapezoid, narrowing on a rear side of the vehicle body 5. A widthof the second exhaust air path 91 in a lateral direction of the vehiclebody 5 is narrower than a lateral width of the first exhaust air path 89at a connection portion to the first exhaust air path 89. The secondexhaust air path 91 extends so as to project from a bottom face of thefirst exhaust air path 89, that is, the sidewall 85 b partitioning theexhaust air path 82.

The second exhaust air path 91 includes the second exhaust port 93opening obliquely backward and downward in the fuel cell vehicle 1behind the rear fender 38 while avoiding the rear fender 38. The secondexhaust port 93 is disposed in a negative pressure region caused duringtraveling of the fuel cell vehicle 1 behind the rear fender 38. Thus,when the fuel cell vehicle 1 travels, exhaust air in the second exhaustair path 91 is sucked through the second exhaust port 93 due to thenegative pressure region behind the rear fender 38. That is, the secondexhaust port 93 enables the exhaust air to effectively flow out. Thesecond exhaust port 93 includes an electrically conductive second meshfilter 95. The second mesh filter 95 prevents foreign objects in a sizeof a few millimeters to a centimeter from entering the exhaust duct 52while maintaining a smooth flow of exhaust air in the second exhaustport 93.

The first duct member 85 and the second duct member 87 work together topartition the first exhaust air path 89, and the first duct member 85itself partitions the second exhaust air path 91. That is, the firstduct member 85 partitions a part of the first exhaust air path 89 andthe second exhaust air path 91, and the second duct member 87 partitionsother portions of the first exhaust air path 89. The other portions ofthe first exhaust air path 89 are on an opposite side to the secondexhaust air path 91, and in an upper portion of the first exhaust airpath 89.

The first duct member 85 includes the continuous rectangular cylindricalconnection portion 81 being provided at a most upstream portionconnected to the fuel cell 2, the first partition wall 83 beingconnected to a downstream side of the connection portion 81 andpartitions a lower half of the first exhaust air path 89 while reachinga rear end of the first duct member 85, a second partition wall 96 beingin the shape of a tube and partitions the second exhaust air path 91.The connection portion 81 has a rectangular tube shape corresponding tothe exhaust port 2 b of the fuel cell 2, and has substantially flatvertical and horizontal walls. The connection portion 81 is very shortin length as compared with overall length of the first exhaust air path89. A gap between the connection portion 81 and the fuel cell 2, thereis provided a seal material (not illustrated) sandwiched to air-tightlyblock.

The first partition wall 83 includes the sidewalls 85 a, 85 b, and 85 cconnected to the rear of the lower half of the connection portion 81 andpartition the exhaust air path 82. The first partition wall 83, that is,the sidewalls 85 a, 85 b, and 85 c form a tray shape opening upward. Alower half of the first exhaust port 73, that is, the right and leftpair of exhaust ports 73 a and 73 b are partitioned at a rear end of thefirst partition wall 83.

The sidewall 85 b of the first partition wall 83 is a bottom wallpartitioning the bottom face of the first exhaust air path 89. In aboundary portion between the connection portion 81 and the sidewall 85b, there is provided a projecting portion 97, in an appropriate shape,projecting inside the exhaust duct 52 to avoid interference between theexhaust duct 52 and the frame 11. The projecting portion 97 has arecessed shape as viewed from the outside of the exhaust duct 52. Thesidewall 85 b has a central portion provided with an openingcommunicating with the second exhaust air path 91. The sidewall 85 b isconnected to the second partition wall 96 in the shape of a tube. Thesecond partition wall 96 projects from the sidewall 85 b to extenddownward.

The second partition wall 96 is fixed to a duct fixing bracket 105 ofthe frame 11 with fasteners 106, for example bolts. The duct fixingbracket 105 also serves as a fixing bracket for the dilution fan 71 andthe rear fender 38, and is provided between rear ends of the right andleft upper frames 25.

The second duct member 87 is a lid detachably assembled from above in aportion of the first duct member 85 behind the connection portion 81.The second duct member 87 partitions a top face of the first exhaust airpath 89 on a downstream side from the connection portion 81. The secondduct member 87 works together with the sidewalls 85 a and 85 c of thefirst partition wall 83 to partition right and left side faces of thefirst exhaust air path 89 on a downstream side from the connectionportion. An upper half of the first exhaust port 73, that is, the rightand left pair of exhaust ports 73 a and 73 b are partitioned at a rearend of the second duct member 87.

The second duct member 87 includes a second joint portion 98 fitted toan edge portion of the first duct member 85 in the divided face 86 so asto cover the edge portion. A gap between the second duct member 87 andthe first duct member 85, there is provided a seal material (notillustrated) sandwiched to air-tightly block. The second duct member 87is detachably fixed to the first duct member 85 with appropriatefasteners 101, for example, bolts provided in the second joint portion98. The second joint portion 98 has an inner surface allowing the secondduct member 87 and the first duct member 85 to be coupled substantiallyflush or flat with each other.

The dilution fan 71 is provided in a lower portion of the exhaust duct52, and is disposed in a posture for blowing rearward of the vehiclebody 5. The dilution fan 71 has a width less than a lateral width in thelateral direction of the vehicle body 5 of the second exhaust air path91, and is disposed in a central portion of the exhaust duct 52 in awidth direction of the vehicle body 5 to be provided in a surface of awall on a front side of the fuel cell vehicle 1 among the sidewallspartitioning the second exhaust air path 91. The wall surface on thefront side is a part of the second partition wall 96 of the first ductmember 85. The wall surface on the front side includes a cut-out portion107 guiding air blown into the exhaust duct 52 from the dilution fan 71.

The dilution fan 71 is fixed in a posture for blowing toward a rear edgeportion of the branching portion between the first exhaust air path 89and the second exhaust air path 91. The dilution fan 71 feeds airbetween the rear fender 38 and the sidewall 85 b, that is, bottom wallof the exhaust duct 52 into the second exhaust air path 91. That is, thedilution fan 71 feeds air in front of the second partition wall 96toward the dilution accelerating wall 72 facing a slightly upstream sideof the second exhaust air path 91.

The dilution accelerating wall 72 is provided in the rear edge portionof the branching portion between the first exhaust air path 89 and thesecond exhaust air path 91 in a boundary portion between the sidewall 85b and the second partition wall 96. The dilution accelerating wall 72projects from the second partition wall 96 into the first exhaust airpath 89 so that the second partition wall 96 of the second exhaust airpath 91 extends upward. The dilution accelerating wall 72 has an upperend portion curving toward the front of the vehicle body 5, that is, theexhaust port 2 b of the fuel cell 2.

The dilution accelerating wall 72 has a width less than a width of eachof the first exhaust air path 89 and the second exhaust air path 91, inthe width direction of the vehicle body 5. The dilution acceleratingwall 72 is disposed in the central portion of the exhaust duct 52 so asto face the dilution fan 71. A portion between left edge of the dilutionaccelerating wall 72 and the sidewalls 85 a has a distance, and aportion between right edge of the dilution accelerating wall 72 and thesidewalls 85 c has a distance. This enables exhaust air of the fuel cell2 to pass to a downstream side of the first exhaust air path 89 throughboth the right and left sides of the dilution accelerating wall 72.

The exterior 12 includes the frame cover 43 with which the rear end ofthe vehicle body 5 is covered, the frame cover 43 being provided withthe first joint portion 75 being fitted to an opening edge of the firstexhaust port 73 of the exhaust duct 52 so as to cover the opening edge.The first joint portion 75 has a similar structure to that of the secondjoint portion 98 between the first duct member 85 and the second ductmember 87. The frame cover 43 is fixed to the exhaust duct 52 with afastener 108, for example, bolt at a portion between the pair of exhaustports 73 a and 73 b. The first joint portion 75 has an inner surfacethat allows the exhaust duct 52 and the frame cover 43 to be coupledsubstantially flush or flat with each other.

The exhaust duct structure 69 also includes a lighting device 109disposed below the first exhaust air path 89 and behind the secondexhaust air path 91.

The lighting device 109 is so-called a tail lamp, and is disposed at thebranching portion between the first exhaust air path 89 and the secondexhaust air path 91. The exhaust duct structure 69 allows the lightingdevice 109 to be disposed between the first exhaust air path 89 and thesecond exhaust air path 91 so as to be closer to the front of thevehicle body 5 as much as possible, thereby reducing overall length ofthe vehicle body 5.

The fuel cell 2 warms up at a low temperature by driving the fan tocirculate exhaust air of fuel cell 2 while the intake shutter and theexhaust shutter are closed. This warm-up operation is calledrecirculation. During the recirculation, while discharging no exhaustair to the exhaust duct 52, the fuel cell 2 continuously purges hydrogengas. That is, during the recirculation, while discharging no exhaust airto the exhaust duct 52, the fuel cell 2 continuously performs hydrogengas purge with hydrogen concentration higher than that of the exhaustair.

Thus, the exhaust duct 52 includes a surplus hydrogen guide passage 112through which surplus hydrogen is guided from the surplus hydrogenexhaust pipe 76 into the exhaust duct 52, the surplus hydrogen beingguided to above the dilution fan 71 and on an upstream side of a flow ofexhaust air in the exhaust duct 52. The surplus hydrogen guide passage112 is provided in a lower portion of the connection portion 81 being anupstream portion of the exhaust duct 52. The fuel cell vehicle 1 allowsthe dilution fan 71 to be operated to reliably dilute surplus hydrogenduring the recirculation.

The surplus hydrogen guide passage 112 communicates with the fuel cell 2through a plurality of surplus hydrogen guide holes 113 penetrating awall of the exhaust duct 52 to communicate with the surplus hydrogenexhaust pipe 76. The surplus hydrogen guide holes 113 are provided in anopening edge of a bottom face of the connection portion 81 of theexhaust duct 52. The surplus hydrogen guide holes 113 are provided onrespective right and left sides of the bottom face of the connectionportion 81.

The surplus hydrogen guide passage 112 is provided in the exhaust duct52. The surplus hydrogen guide passage 112 is a part of a flow channelof surplus hydrogen guided into the exhaust duct 52 through theplurality of surplus hydrogen guide holes 113. The surplus hydrogenguide passage 112 includes a tunnel cover 115 working together with aninner surface of the exhaust duct 52 to guide surplus hydrogen to thecentral portion of the exhaust duct 52 in its width direction. Thetunnel cover 115 constitutes a pair of tunnel covers 115 disposed alongan opening edge of the connection portion 81 to cover the respectiveright and left surplus hydrogen guide holes 113, the pair of tunnelcovers 115 each having an opening in an central portion of the exhaustduct 52. The tunnel cover 115 guides surplus hydrogen caused by hydrogengas purge flowing through the surplus hydrogen guide hole 113 to acentral portion in a width direction of the exhaust duct 52 to allow thesurplus hydrogen to be discharged into the exhaust duct 52.

The tunnel cover 115 includes a plurality of exhaust holes 116 alignedin the width direction of the vehicle body 5. The exhaust holes 116allow hydrogen to be discharged into the exhaust duct 52 whiledispersing the hydrogen by effectively using overall width of theexhaust duct 52, along with an opening end of the tunnel cover 115, thatis, the central portion of the exhaust duct 52.

The fuel cell vehicle 1 according to the present embodiment includes thedilution fan 71 guiding air into the exhaust duct 52 to dilute hydrogenin the exhaust duct 52, and thus ensures that the hydrogen is stirredand diluted to improve efficiency of discharging exhaust air to theoutside of the fuel cell vehicle 1.

Further, the fuel cell vehicle 1 according to the present embodimentincludes the dilution fan 71 being provided in a lower portion of theexhaust duct 52, and thus even if the dilution fan 71 fails and stops,hydrogen can be discharged from the first exhaust port 73 by preventingthe hydrogen from flowing out to the outside of the fuel cell vehicle 1through the dilution fan 71.

Further, the fuel cell vehicle 1 according to the present embodimentincludes the dilution fan 71 being disposed to blow rearward the rear ofthe vehicle body 5, and thus air can be smoothly guided into the exhaustduct 52 without interfering with travelling wind, and also can beallowed to smoothly flow to the first exhaust port 73.

Further, the fuel cell vehicle 1 according to the present embodimentallows the dilution fan 71 to blow air to the dilution accelerating wall72 in the exhaust duct 52, and thus dilution of hydrogen can beaccelerated by generating a stirring flow in the exhaust duct 52.

Further, the fuel cell vehicle 1 according to the present embodimentincludes the surplus hydrogen guide passage 112 guiding surplus hydrogento above the dilution fan 71 and on an upstream side of a flow ofexhaust air in the exhaust duct 52, and thus hydrogen discharged intothe exhaust duct 52 by hydrogen gas purge can be reliably stirred anddiluted while being sucked into a flow of air generated by the dilutionfan 71.

Further, the fuel cell vehicle 1 according to the present embodimentincludes the tunnel cover 115, and thus the hydrogen discharged into theexhaust duct 52 by the hydrogen gas purge can be more reliably guided tothe dilution fan 71.

Further, the fuel cell vehicle 1 according to the present embodimentincludes the tunnel cover 115 to have the plurality of exhaust holes,and thus dispersion of the hydrogen discharged into the exhaust duct 52can be accelerated.

Therefore, the exhaust duct structure 69 of the fuel cell vehicle 1according to the present invention ensures that hydrogen flowing intothe exhaust duct 52 is diluted.

What is claimed is:
 1. A fuel cell vehicle comprising: a vehicle body; an air-cooled fuel cell mounted in the vehicle body to generate power by allowing hydrogen gas and oxygen in air to react with each other; an exhaust duct through which exhaust air of the fuel cell is guided to a rear end of the vehicle body and is discharged outside the fuel cell vehicle; and a fan guiding air into the exhaust duct to dilute hydrogen in the exhaust duct, wherein the fuel cell includes a surplus hydrogen exhaust pipe discharging unreacted surplus hydrogen and the exhaust duct includes a surplus hydrogen guide passage through which the surplus hydrogen is guided from the surplus hydrogen exhaust pipe into the exhaust duct, the surplus hydrogen being guided to above the fan and on an upstream side of a flow of exhaust air in the exhaust duct, and wherein the fan is disposed in a central portion of the exhaust duct in a width direction of the vehicle body, the surplus hydrogen guide passage includes a tunnel cover covering a plurality of surplus hydrogen guide holes penetrating a wall of the exhaust duct to communicate with the surplus hydrogen exhaust pipe, the tunnel cover collecting the surplus hydrogen guided into the exhaust duct through the surplus hydrogen guide holes to collect the surplus hydrogen to a central portion of the exhaust duct in a width direction of the vehicle body, the tunnel cover including a plurality of exhaust holes.
 2. The fuel cell vehicle according to claim 1, wherein the fan is provided in a lower portion of the exhaust duct, and is arranged to blow rearward of the vehicle body.
 3. The fuel cell vehicle according to claim 1, further comprising: a dilution accelerating wall provided inside the exhaust duct and facing the fan to disperse a flow generated by the fan into the exhaust duct for acceleration of dilution of hydrogen.
 4. The fuel cell vehicle according to claim 2, further comprising: a dilution accelerating wall provided inside the exhaust duct and facing the fan to disperse a flow generated by the fan into the exhaust duct for acceleration of dilution of hydrogen. 